A kind of honeybees can clone themselves perfectly 一種會(huì)完美克隆自己的蜜蜂

劉同功

南非的一只海角蜂工蜂因?yàn)閾碛泻币姷幕蛱刭|(zhì)，可以通過克隆自己來實(shí)現(xiàn)自行繁衍。在過去的30多年里，這只海角蜂工蜂已經(jīng)成功地克隆出數(shù)百萬只“自己”，這個(gè)發(fā)現(xiàn)刷新了人們的認(rèn)知。

A kind of South African honeybees can clone themselves and create more bees like them. Genetic analysis reveals that their cloning habit began on a single honeybee in 1990 that cloned itself successfully and produced queens that could take over the hive， according to New Scientist.

The process of asexual reproduction or parthenogenesis （單性生殖） is common in lower plants or animals， like ants， wasps， and bees. However， having an offspring that is identical to the parent is uncommon because genetic material is often mixed up in a process called recombination that could result in an offspring with a slightly different genetic make?up.

It was previously known as the subspecies（亞種） of the Cape honeybee that is capable of creating a perfect copy of itself， according to Benjamin Oldroyd of the University of Sydney. He added that creating clones that are perfect copies of the parent could be beneficial as asexual reproduction could often be deadly because one?third of the genes become inbred. But since the Cape honeybee workers are perfect clones， they remain genetically healthy as their mother.

“Its incredible. Its also incredibly rare，” Oldroyd told Live Science， referring to the DNA reorganizing method necessary to hold chromosomes （染色體） together during the egg?making process of the honeybees that clone themselves. “Yet， somehow theyve managed to do it. Ive not heard of anything like this before， anywhere”.

The generations of parthenogenetic reproduction have contributed to the loss of genetic material that led to low levels of genetic diversity that are deadly. Most social insects rely on their queen to reproduce， while workers help maintain the colony and protect the brood （一窩動(dòng)物）.

But in the Cape honeybees case， workers do not work because they can asexually reproduce. Oldroyd said that these bees seemed to develop a rare attitude that leads to the collapse of the hive. He compared it to cells in a tumor in which it does not matter whether the clones are healthy， as long as there is enough of them to exploit the host.

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1. What do we know about the underlined word “parthenogenesis” from paragrpah 2？

A. It doesnt exist in living things.

B. It exists only in complex plants.

C. It exists only in simple animals.

D. Its seldom found in higher animals.